When Mopar first debuted the unibody style of automotive building for their full line of cars, this new style of car building was touted as making the car stronger and safer. When a car is new, this might be the case. But add thirty of more years of driving across bumpy roads and/or the occasional crash, and things tend to “loosen” up a bit. When I say loosen up, I mean that welds can break, metal can fatigue, and the body tends to flex a little more than it did when it was new. Not only can normal driving loosen up a unibody’s construction, but since most of us are playing with our cars, it’s safe to say that there have been more than just a few engine swaps done over the years to increase horsepower.

Since our project ’Bee was built in 1970, and we didn’t buy it new, it’s really hard to say what kind of life it had. The only thing we were told by the previous owner was that the original engine was blown up a long time ago. Now, the plan is for us to install a stroked out 440 with slightly more horsepower than the factory delivered in any ’70 Superbee. So, while the car is at Unlawful Racing, we decided that a simple rollbar (read: not necessarily NHRA approved), and their Chassis Stiffening Bars were going to be an added necessity to this car. While climbing over a rollbar can be tricky for some, and use of the rear seat is usually not an option anymore, our theory is that we can deal with tricky, and we don’t foresee any of us needing to get into the back seat anyway.

The Chassis Stiffening Bars from Unlawful are a direct bolt-in unit that ties the rear framerails with the front framerails, and also ties the left side of the car with the right side. It even incorporates a bolt-in driveshaft safety loop, which is a nice, added benefit. The rollbar is a custom-bent piece made of 15⁄8-inch .120-inch thick wall tubing that fits the car nicely, and still adds a ton of support to the body. We didn’t want the roll bar to be a complete hindrance when getting in and out of the car, but give the body some added stiffness.

Finally, we wanted to upgrade and improve our rear suspension. When new, our ‘Bee, like any Mopar muscle car, came from the factory with a leaf spring rear suspension. Leaf spring design has come a long way since the tried and true Super Stock spring upgrade of the ’70s, but we decided to take advantage of a new mousetrap (so to speak). Unlawful Racing manufactures a triangulated four-link suspension that eliminates the leaf springs. In a leaf spring suspension, the springs perform two distinct functions. First, they hold the rear axle of the car in place, and secondly, they prevent both forward and rearward movement of the rear end. Under normal circumstances, they also minimize pinion angle change during suspension travel. Try to launch the car from a stop light, and the springs try to “wrap up,” changing the pinion angle. This causes wheel hop and loss of traction. Secondly, they also support the vehicle’s weight. For a stock vehicle that will operate within a predictable range of suspension travel, leaf springs do an adequate job. The problem occurs when the intended usage is changed (i.e. lower ride height, more horsepower, and/or different weight distribution characteristics). The leaf springs can’t perform as intended if the intended usage deviates far from the original usage. With a four link suspension, the function of locating the rear axle and supporting the vehicle are now done by two different pieces; the four link and the coil-over shock absorbers. With a four-link suspension you have the ability to properly locate the rear axle no matter how soft you want to make the spring on the coil over for ride comfort. With a leaf spring rear suspension, softening the spring rate can cause other problems such as a sagging rear end of your car, or an ill-handling car.

9/15<strong>6.</strong> Building a modern muscle car can be done many ways. We chose to upgrade/improve our ’Bee with the addition of a triangulated four-link rear suspension.

Installing the rear suspension and the roll bar do require a welder, and are a little more than a novice might want to try and tackle. The Chassis Stiffening Bars are a simple bolt-in design that can be welded in place, and will give the average Mopar a great improvement in its handling characteristics by itself.